1. Field of the Invention
The present invention relates to a tractor having a backhoe attached to a rear side thereof.
2. Description of the Related Art
According to a conventional tractor with a backhoe of the above-noted type, the tractor includes a frame detachably attached to the rear portion of the tractor. To the rear portion of this frame, a swing bracket is supported to be pivotable about a vertical axis. To a rear lower portion of the swing bracket, a base portion of a boom is pivotally connected to be pivotable about a right/left axis. To the leading end of the boom, an arm is pivotally connected to be pivotable about a right/left axis. To the leading end of the arm, a bucket is pivotally connected to be pivotable about a right/left axis. And, on the right and left opposed sides of the frame, outriggers are attached. Then, these components, i.e. the swing bracket, the boom, the arm, the bucket, the outriggers, are all operated by means of hydraulic cylinders. Further, a separate step is mounted above an upper wall of the frame, and on this step, there is fixedly mounted a control box which accommodates therein a control valve unit comprised of an assembly of control valves for controlling the respective hydraulic cylinders for operating the swing bracket, the boom, the arm, the bucket, and the outriggers (see JP-A-2003-20674 and JP-A-2000-345582).
According to another known tractor with a backhoe of the above type, the boom cylinder for operating the boom is inserted in the boom and one end of the boom cylinder is pivotally connected to a rear upper portion of the swing bracket. The arm cylinder for operating the arm is disposed on the upper side of the boom and along this boom. The bucket cylinder for operating the bucket is disposed on the rear face side of the arm and along this arm. Hydraulic hoses for feeding pressure oil to these hydraulic cylinders are arranged from the rear face of the control valve unit to the rear side. Then, the hoses are extended between a boom cylinder pivot portion provided at the rear upper portion of the swing bracket and the pivot portion of the swing bracket relative to the frame, and then between the boom cylinder pivot portion and the boom pivot portion to be inserted eventually into the boom (see JP-A-2000-345582).
With such tractor with a backhoe, generally, it is possible to e.g. stabilize the work by drawing the work device having the boom, the arm and the bucket as forward as possible (i.e. as close to the tractor as possible) by drawing the base portion of the boom as forward as possible (i.e. as close to the tractor as possible). However, with the conventional construction described above, the control valve unit is disposed on the upper side of the frame and the hydraulic hoses for the boom cylinder, the arm cylinder, and the bucket cylinder are extended between the boom cylinder pivot portion provided at the rear upper portion of the swing bracket and the pivot portion of the swing bracket relative to the frame, and then between the boom cylinder pivot portion and the boom pivot portion to be inserted eventually into the boom. This construction requires securing of a space for inserting the hydraulic hoses between the boom cylinder pivot portion and the swing bracket pivot portion. This requirement imposes limit in drawing the base portion of the boom forward, or close to the tractor.